1. Field of the Invention
This invention relates to a method and apparatus for annealing glassware and the like by directing the annealing medium to the inside and outside of the ware simultaneously for rapid and uniform treatment of each product being treated while maintaining independent temperature control in a series of communicating zones through which the ware travels.
2. Description of the Prior Art
Automated zonal lehrs for high quality annealing described and claimed in my Pats. Nos. 3,010,710, 3,261,596 and 3,371,430 are in general use throughout the United States and Canada and are recognized as a system of annealing that provides better temperature control from the charge to the discharge end of the lehr tunnel. Prior to the introduction of the zonal control system, the heat curve for preheating and annealing was maintained by the application of heat and cooling media transversely of the tunnel in increments longitudinally of the tunnel. This method required relatively long lehr tunnels that took up a lot of needed space because of the necessary slow travel of the lehr conveyor belt. This allowed limited production for the required annealing time.
These prior art annealing systems utilized special equipment for charging the glassware to the lehr conveyor belts which employed star-wheel transfer mechanism and transverse conveyors, push bar stackers, spray-on packing tables, unscramblers and the like, which are eliminated in the single line conveyor type lehrs of this invention where the ware is transferred directly from the forming machine to the lehr conveyor belt. The single line conveyor may be directed through a wider and much shorter lehr with a plurality of parallel adjacent tunnels and a continuous conveyor passing therethrough.
The jet firing to the inside and outside of the ware allows for rapid annealing superior to treating from outside the ware only. By combining the jet firing treatment with the zonal controls of my former patents referred to above, the annealing time is substantially reduced. By this method a gallon container has been annealed in one-fourth the time with a conveyor belt travel of from 40 to 60 feet per minute. The annealing of glassware and the like by the present method will greatly reduce the cost of producing glassware.